Marissa Mayer's decision to terminate telecommuting arrangements for Yahoo! employees has ignited a frenzy of negative press. Articles cite how studies have shown that telecommuting arrangements lead to more happier and productive employees. How could Mayer have been so stupid and shortsighted? Surely, this signals the downfall of Yahoo.
Interestingly, when I hear reports from people who work at Yahoo!, they're almost invariably positive about this change. Some excerpts from a Quora question about this:

#1: I have been at Yahoo for four years and let's just say the house needed and still needs a lot of cleaning up and Marissa is doing just that. So I am glad that the change in policy was made.

#2: Another current and longterm Yahoo developer here, who is extremely happy that the WFH shenanigans are being put to an end. I too have seen this abused far too often, although IMO it's usually not by full time WFH, but more often the San Francisco city dweller who just happens to spend two, sometimes three, days of the week working from his house because "the commute to Sunnyvale is too tiring". Hey, clue people.. nobody made you live in San Francisco.

#3: from the perspective of my time there this is a much needed policy. I saw many people abuse the work at home policy. In fact it was a running joke that a large percentage of employees basically did no work on Fridays.

#4: I think its a great thing for the company. I have been at Yahoo! for 5 years and Marissa is doing a much needed house cleaning. There is still some good talent here but we need all hands on deck and thoses who are not team players can just bow out.

#5: I personally am very happy with not being allowed to work from home. And to be honest, my family loves me more since I started leaving my work at work. Most of my other colleagues too are very happy.

These aren't just choice excerpts. There are five responses from Yahoo! employees about this change; all five are positive. When I read comments in news articles about this policy from Yahoo! employees, they are also almost universally positive. As far as I can see, the people who hate this change are the people who don't even work there.

Regardless of how you might personally feel about working from home for you or your company, it didn't seem to be working for Yahoo!.

But haven't studies shown that telecommuting is a good thing?

Quite simply: no.

The "studies" people cite on this is really just one study that showed a 13% productivity gain. Before you get all excited, realize the following:

This study was done in China, not the US. China and the US have very different work cultures with very different approaches to collaboration, management, and company culture. The results from one country do not necessarily apply to the other.

This study was conducted on call-center employees. The results of this cannot be applied to many or most other jobs.
(a) Call-center employees have little need for collaboration. Most of the work is solitary, and thus team work won't be impacted.
(b) Call-center employee productivity is easily measured. If someone is slacking off, it's obvious.
(c) Call-center work is pushed out to employees; they aren't volunteering to take on projects, which they then work through at their own pace.
In other words, it's a lot easier to be productive at home as a call-center employee than it is as, for example, a software developer.

The productive gain was 13% -- significant, but not enormous. And, the vast majority of that productivity again is due to a reduction in sick days. In other words, the vast majority of the gain could have been achieved by just allowing employees to work from home when they're sick.

This is no big surprise from me. When I talked to friends and colleagues at tech companies, almost everyone admits that they aren't very productive when they work from home.

This doesn't mean that telecommuting doesn't work for anyone or for any companies. Some people have found ways that it works well for them. Some companies have been able to set up very effective distributed work environment (of course, I've only heard of this being done effectively for certain roles or for very small companies). I'm sure it can work for some people, but it's not the norm.

Ultimately, regardless of what studies reveal, every company is different and it's Marissa Mayer's responsibility as CEO to make the decisions that are best for her company. She isn't making the decision willy-nilly. She's been with Yahoo for long enough to understand whether or not it's working for the company. If she's decided that it's not working for Yahoo!, she's probably right. And, she's given the telecommuting employees four months to comply with the new policy; this is hardly extreme or unfair.